On the Ethereal Plane. An ethereal creature is invisible, inaudible, insubstantial, and scentless to creatures on the Material Plane, but visible and corporeal to creatures on the Ethereal Plane. As such, such a creature is capable of moving through solid objects on the Material Plane and in any direction (even up or down), though all movement is at half speed. Most magical attacks have no effect on them. See invisibility and true seeing reveal ethereal creatures.
Ethereal beings can see and hear what is happening in the same area of the Material Plane to a distance of 60 feet, though material objects still block sight and sound. (An ethereal creature can't see through a material wall, for instance.) Things on the Material Plane, however, look gray, indistinct, and ghostly. An ethereal creature can't affect the Material Plane, not even magically. An ethereal creature, however, interacts with other ethereal creatures and objects the way material creatures interact with material creatures and objects.
Even if a creature on the Material Plane can see an ethereal creature (for instance, with see invisibility), the ethereal creature is on another plane. Only force effects (such as magic missile) can affect the ethereal creatures. If, on the other hand, both creatures are ethereal, they can affect each other normally.
A force effect originating on the Material Plane extends onto the Ethereal Plane, so that a wall of force blocks an ethereal creature, and a magic missile can strike one (provided the spellcaster can see the ethereal target). Gaze effects and abjurations also extend from the Material Plane to the Ethereal Plane. None of these effects extend from the Ethereal Plane to the Material Plane.
Ethereal creatures move in any direction (including up or down) at will. They do not need to walk on the ground, and material objects don't block them (though they can't see while their eyes are within solid material).
Ghosts have a power called manifestation that allows them to appear on the Material Plane as incorporeal creatures. Still, they are on the Ethereal Plane, and another ethereal creature can interact normally with a manifesting ghost.
Ethereal creatures pass through and operate in water as easily as air.
Ethereal creatures do not fall or take falling damage.